I believe, if I am not mistaken, that Matchbot looks at all the names that could be last names (LNAB, Current Last Name, etc) to see if there is a match.
In the example above, the first profile and second profile both have Lewis as their Current Name even though one is a maiden name and one is a married name - technically they are a match. A human would know by looking that it is two different things but the computer doesn't. That is why we have a team that tries to go through the MatchBot proposed merges to eliminate the ones that are obvious non-matches.
But MatchBot does propose valid matches. Yesterday, for example, it pointed out a match where I ended up creating another six merge requests for her family members.
Hopefully you can weigh the good with the bad for now and the MatchBot Team will work to get things tweaked in the match criteria.
Susan - MatchBot MP